Field of Invention
The present invention relates to the LED technical field and more particularly to a heat conductive technology for an LED lamp core and the interior of an LED chip.
Description of Related Arts
The heat dissipating problem is a key technical problem serving as a bottleneck for the wide spreading of the LED illumination. Since an LED chip requires to dissipate heat, it is hard for an LED illuminating lamp to perform like an incandescent lamp, fluorescent lamp, and etc. with the light bulb being as a standardized component as well as be convenient to assemble, so that the cost is even higher.
An analysis from a single viewpoint of heat transmission theory suggests that the heat dissipating process of LEDs is not complicated. However, the heat transmission theory, mature heat transmission technology, and other basic knowledge related to heat transmission are not fully acknowledged by the people skilled in the art of LEDs, so that the current LED heat dissipating technology and products are complicated.
A heat transferring process from an LED node to an air convection heat exchanging surface (radiator) is a heat conduction process. Because an area of an LED chip is relatively small whilst a heat flux density is significantly high, the heat conduction process actually plays a very important role in the whole LED heat dissipating procedure. An effective and simple solution for reducing a heat resistance of the heat conduction process is to employ a high heat conductive material such as copper and aluminum. However, copper and aluminum are both metal conductors. An LED illuminating device, as an electric appliance, should meet the requirement of safe use of the electricity, so that a predetermined insulating effect should be ensured between the LED node and the radiator (metallic exploded components). A typical insulation requirement is to withstand at least a kilovoltage. Insulation and heat conduction are somewhat incompatible. In a current product, an LED wafer is provided on a ceramic insulation substrate so that high voltage withstanding capability and not low thermal conductivity are made use of so as to solve the problem. The ceramic such as Al2O3 ceramic material has a thermal conductivity up to 20 W/m·K, but is still 10 times smaller than aluminum and about twenty times smaller than copper. And the heat flux density on the LED wafer is high as 106 W/m2. When a 0.2 mm Al2O3 insulation substrate is employed, a temperature difference of heat conduction on the insulation substrate amounts to 10° C.